Manufacture of food extract from yeast



March 7, 1939. J. H. MILLAR MANUFAOTURE OF FOOD EXTRACT FR Filed June 6, 1955 OM YEAST 3 Sheets-Sheet l Jmesw Mimw INVENTOR 1 March 1939- J. H. MILLAR MANUFACTURE OF FOOD EXTRACT FROM YEAS Filed June 6, 1.955 3 Sheets-Sheet 2 \NVENTOIEV March 7, 1939. J. H vMll L AR 2,149,306

MANUFACTURE OF FOOD EXTRACT FROM'YEAST 3 Shee ts-Sheet 5 Filed June 6, 1935 3am. lu Min NVE Patented Mar.

ifUNlTED STATES PATENT OFFICE I MANUFACTURE 021E252; EXTRACT FROM which is rich in James Hill Millar, Dublin, Irish Free State, as-

signor to Arthur Guinness, Son and Company Limited,

In Irish hop extract.

I know that several processes have been proposed fo the debitten'ng of crude yeast extract extract.

The object of removed and any s agulation of protein matter.

4 then be truly claime In the production ers yeast outstandi follows:-

colloidal and residues of theyeas mall residue enclosed by co- The product can a food extract from brewdifliculties were found as t cells.

2. To secure rapid filtration of the crude extract from (1) in colloidal carbon mo 3.'To' secure rapid filtration of the extract London, Englal d Application June 6, 1935, Serial No. Free State 25,216 June 22, 1934 (01. 99-97) I flavours, and to precipitate removed rifuge by another collector preferably of the same or similar type but with larger ports.

The product produced by the process hereinbefore described forms a new yeast and not requiring added flavours from other sources.

The accompanying drawings show, by way of example, means comprising filtering and separating apparatus for carrying out the process in accordance with this invention.

Fig. 1 is a part sectional elevation of a centri- .at'an angle so as fuge for separating the extract from the insoluble matter in accordance with the, invention.

Fig. 2 is a plan view corresponding to .Fig. 1.

Fig. 3 is a part sectional elevation of a filtering and separating centrifuge in accordance with the invention.

Fig. 3 is an enlarged sectional view of a portion of the filtering and separating centrifuge illustrated at Fig. 3.

Fig. 4 is a Fig. 5 is a cross sectional Y--Y Fig. 2 and looking in the arrow. 7/

Figs. 6 and '7 are respectively enlarged plan and end views of the collector blade for collecting filtered liquid from the centrifuge.

Figs. 8 and 9 are respectively plan and end views of the collector blade for collecting sludge from the centrifuge shown in Fig. 1.

Referring to 'the drawings, the centrifuge of known construction but has embodied therein the special forms of collecting devices and th iroperating screw as hereinafter described. The crude pressed yeast is first liquefied by agitation in a suitable mixing machine (not shown) and at a suitable temperature, for example, 65 C., with the addition of a small quantity of common salt. The yeast is then digested in a suitable digesting vessel (not shown) for a lengthy period, (say 72 hours) at or about the same temperature, preferably a temperature of 65 C. is adopted as being the: best for flavour. The resultant semi-fluid mass is diluted ,to a specificgravity of about 1030 (water 1000) in order to and difference of insoluble portions to permit of their subsequent separation in the centrifuge shown in Fig. 1 This centrifuge comprises a bowl I rotatably mounted within a casing I and adapted to be driven by a motor arranged within a casing 2. The liquefied, digested and diluted yeast is fed from the digesting vessel into the centrifuge bowl I throughpipe I. For the collection of the filtered liquid from the continuously running centrifuge and for the removal of the insoluble matter which collects as a dense p'asty sediment on the sides of the centrifuge to overcome the exceptional difficulties which arise in collecting clear liquids from yeast extracts owing to their extremely frothy nature, I employ a form of collector which is adapted to give sharp separation of extract and insoluble matter and also adapted to overcome the difficulty of frothwith sharpened leading and and l respect vely adapted .to

The collecting edge is submerged I preventing the inclusion of air and formation of froth. The interior of the collecting blade division members or vanes 4 leading inwardly from ports 4 on its collecting edge and arranged to collect the liquid with the least possible disturbance of the sediment in the centrifuge bowl. The collector blade 5 is formed in one with a pipe 4' which is secured to a bracket 5, said bracket being removably carried by a member 5 having holes theiein adapted to receive pins 5" projecting from the bracket 5 (see Fig. 5). For removing the insoluble sediment from the centrifuge another collector 8 is provided and is also carried by the bracket 5', the blade of this collector is illustratedat Figs. 8 and ployed consists of adsorptive constituent, for example, apulp comprising asbestos 10%- -cellulose 90%. By varying clear liquid except that the ports in its collecting edge are larger than the ports in the collecting edge'of the collector for the clear liquid. This collector 8 is formed in one with a pipe 8 leading the from the centrifuge. The collectors are kept submerged during collection by screw control gear consisting of the screw 1 the bracket carrying member 6 which engages the screw and an operating wheel 9. The screw 1 and 1 carriedby inwardly projecting flange this arrangement the bracket carrying member 6 can be moved to keep the leading edge of the collector submerged in the liquid to take only clear or filtered liquid, also to prevent the inclusion of air and the formation of .froth. Below the screw 1 is a rod In which is secured to the top inwardly projecting flange I of the centrifuge and carries stops Ill (see Fig. 5) to limit the outward movement of the collectors and the bracket carrying member 6 has secured thereto an indicating member 65 adapted to move over a graduated scale II for indicating the position of the collector, and for its accurate adjustment uid may pass into the collector. Turning the screw 1 in one direction brings the clear liquid collector 4 into collecting position and at the same time takes the sludge collecting device 8 out of action and vice-versa.

The crude liquid extract from the centrifuge shown in Figs. 1 and 2 passed from pipe 4 to the pipe i1 is still muddy in appearance from the presence of yeast suspended matter and requires filtration to make it bright, (otherwise the removal of activated carbon at a subsequent stage is more difficult) such filtration being carried out by leading the separated liquid from pipe l1 into the novel form of centrifuge-filter shown at Figs. 3 and 4 and which is characterized by a centrifpge bowl l2 which is dividedinto two chambers or compartments, a charging chamber [2 and a discharging chamber I!" by means of a horizontal diaphragm or inwardly projecting ring or plate l3 having clearance gaps, obtained by means of distance pieces l3 between its outer edge and the inner surfaceof the bowl l2. A gauze apron M is provided below the said diaphragm or plate IS, with a gap I5 between it and the inner surface of the bowl, which gap may be considered as part of the discharging chamber If the upper edge of the apron I4 being attached to and carried by 9. depending ring l3 on the outer edge of the diaphragm or plate I3, which ring l3 extends downwards a predetermined distance (approximately as shown) below the under side of the before mentioned diaphragm or plate. 13. The required filter material l6, fed with a suitable carrier liquid, into the lower portion l2 of the bowl I! through a hopper i8 and pipe I8, is applied to the gauze apron ll by from the underside of the plate l3 to the gap between the bottom of the gauze I4 and ring or the like l5 so that the extract has no alternative but to pass through the filter and short circuiting and uneven flow are prevented and effective filtration is ensured. Preferably the filtering material ema layer of pulp with ,a special the speed of the centrifuge and the proportions 9 and is similar to 'thecollector blades for the required'iiltration of liquids or semi-liquid'mateother undesirable flavours;

rials difl'ering in character. Smooth action filter medium can times g. as a standard.

After filtration and concentration, as described, the temperature of the filtered liquid is brought to say, a two inch layer of filtering pulp preferably consisting of 60% to 80% cellulose and 40% asbestos applied and plain or ordinary After evaporation further to precipitate unwanted solids, and to product of manufacture.

What I claim is: 1. In a process of manufacturing a soluble food extract from brewers yeast, which includes sepasubjecting the extract to plain or ordinary centrifuging to remove the or remove the last traceof carbon.

The process of manufacturing a soluble food from brewers yeast which comprises for about C. to destroy proteolytic enzymes and produce coagulation of protein matter evaporating to obtain the flnal product.

3. The process of manufacturing a soluble food extract from brewers ing the extract by evaporation, heating same to about 70 C. and maintaining at said temperature for about an hour while about 0.75%

tion of protein matter to enclose or remove the last trace of carbon.

6. A process for treating extract of 'yeast, produced by self-peptonisation comprising liquefying the yeast, digesting the liquid, diluting the digested mass, separating by centrifuging, then subjecting the centrifuged extract to centrifugal filtration, concentrating the filtered extract in vacuo to remove some objectionableefiavours and to precipitate undesirable solids, heating the extract and treating same with activated carbon to remove bitter and other undesirable flavours, subjecting the extract to ordinary centrifuging to emove the suspended carbon and to filtration i a centrifuge to remove the remaining carbon which is colloidally dispersed, evaporating the filtered extract in vacuo to a thick paste further to precipitate unwanted solids, redissclving the paste in hot water to destroy proteolytic enzymes and produce coagulation of protein matter to enclose or remove the last trace of carbon, centrifuging the extract and then finally evaporating to a thick paste.

'1. The process of manufacturing a soluble food extract from brewers yeast which comprises liquefying the crude yeast at a raised temperature, digesting the liquid for a lengthy period at said temperature, diluting the mass, and centrifuging to remove insoluble matter, further subjecting the extract to centrifugal filtration, concentrating the" extract by evaporation, heating same and maintaining said heating for about an hour while a small percentage by volume of activated carbon is gradually added, subjecting the extract to plain or ordinary centrifuging to remove the suspended carbon and then to centrifugal filtration through an adsorptive filter to remove the colloidally dispersed carbon, ing the extract in vacuo to a thick paste, redissolving the paste in hot water and heating to a temperature sufllcient to destroy proteolytic enzymes and produce coagulation of protein matter to enclose or remove the last trace of carbon and subjecting the heated liquid to centrifuging and N evaporating to obtain the final product.

JAMESHIILMILPAR. 3o 

